Wide-temperature-range uniaxial and biaxial compression test device in high-pressure hydrogen environment

1. A wide-temperature-range uniaxial and biaxial compression test device in a high-pressure hydrogen environment, comprising a test box, a temperature sensor, a gas pressure sensor, test pressure sensors, displacement sensors, an oxygen/hydrogen concentration monitor, an upper computer, a hydrogen filling system, a vacuum extraction system, and a Digital Image Correlation (DIC) test system, wherein a sample clamping mechanism, a heating system and a cooling system are arranged in the test box; the upper computer is electrically connected to the temperature sensor, the gas pressure sensor, the test pressure sensors, the displacement sensors, the oxygen/hydrogen concentration monitor, the hydrogen filling system, the DIC test system, the sample clamping mechanism, the heating system, the vacuum extraction system and the cooling system, respectively; the hydrogen filling system is connected to the test box through a pipeline; the temperature sensor, the gas pressure sensor and the oxygen/hydrogen concentration monitor are arranged inside the test box; the vacuum extraction system is connected to the hydrogen filling system and the test box through a pipeline, respectively; a uniaxial compression test mode and a biaxial compression test mode are implanted in the upper computer; the upper computer is configured to acquire test parameters in the uniaxial compression test mode or the biaxial compression test mode, and to generate a test instruction based on the test parameters; the test instruction is configured to start the hydrogen filling system, the temperature sensor, the gas pressure sensor, the test pressure sensors, the displacement sensors and the oxygen/hydrogen concentration monitor; the test pressure sensors and the displacement sensors are arranged on the sample clamping mechanism; the hydrogen filling system is configured to fill hydrogen into the test box; the upper computer is configured to generate a hydrogen filling instruction based on a gas pressure in the test box acquired by the gas pressure sensor; the hydrogen filling system is configured to execute the hydrogen filling instruction; the upper computer is configured to acquire temperature data in the test box acquired by the temperature sensor, and to generate a heating/cooling instruction based on the temperature data; the heating system and the cooling system are configured to execute the heating/cooling instruction until temperature in the test box reaches a set value; the upper computer is configured to generate a sample clamping instruction based on the test parameters; the sample clamping mechanism is configured to execute the sample clamping instruction; the upper computer is configured to acquire data acquired by the test pressure sensors and data acquired by the displacement sensors, and to determine a compression rate of a sample according to the data acquired by the test pressure sensors and the data acquired by the displacement sensors; when the compression rate of the sample reaches the set value, the upper computer generates a sample clamping stop instruction; the sample clamping mechanism is configured to execute the sample clamping stop instruction; the DIC test system is configured to acquire sample image data during the test process; the upper computer is configured to determine stress-strain data of the sample based on the sample image data and the data acquired by the test pressure sensors, to obtain a constitutive model for characterizing nonlinearity of the sample by screening from a database based on the stress-strain data, and to generate a strain distribution nephogram of the sample based on the constitutive model, to analyze a change process of the strain distribution nephogram to obtain a deformation behavior and a failure fracture mechanism of a sample material; and the vacuum extraction system is configured to vacuumize the test box; the hydrogen filling system comprises a nitrogen gas cylinder, a hydrogen gas cylinder, a buffer tank, a first tee joint, and a second tee joint; the nitrogen gas cylinder is connected to a first interface of the first tee joint through a pipeline; a gas molecular filter and a nitrogen manually-operated valve are arranged on the pipeline between the nitrogen gas cylinder and the first interface of the first tee joint in sequence; the hydrogen gas cylinder is connected to a second interface of the first tee joint through a pipeline, and a gas molecular filter and a hydrogen manually-operated valve are arranged on the pipeline between the hydrogen gas cylinder and the second interface of the first tee joint in sequence; a third interface of the first tee joint is connected to a pipeline of a cooler; the cooler is connected to the buffer tank through a pipeline; a pressure sensor, a pressure gauge, an electromagnetic pneumatic valve and a booster pump are arranged on the pipeline between the third interface of the first tee joint and the cooler in sequence; the buffer tank is connected to a first interface of the second tee joint through a pipeline; a second interface of the second tee joint is connected to the test box through a pipeline, a further pressure sensor and a further pressure gauge are arranged on the pipeline connecting the second interface of the second tee joint and the test box, and a third interface of the second tee joint is connected to the vacuum extraction system through a pipeline.

2. The wide-temperature-range uniaxial and biaxial compression test device in the high-pressure hydrogen environment according to claim 1, wherein: the vacuum extraction system comprises a vacuum pump, a third tee joint, and an exhaust port; a first interface of the third tee joint is connected to the hydrogen filling system through a pipeline; a second interface of the third tee joint is connected to the vacuum pump through a pipeline, and a manually-operated valve and a vacuum gauge are arranged on the pipeline connecting the second interface of the third tee joint and the vacuum pump in sequence; and a third interface of the third tee joint is connected to the exhaust port through a pipeline; and an emptying valve is arranged on the pipeline connecting the third interface of the third tee joint and the exhaust port.

3. The wide-temperature-range uniaxial and biaxial compression test device in the high-pressure hydrogen environment according to claim 1, wherein: the DIC test system comprises a camera, and an illuminating lamp; the camera is electrically connected to the upper computer; the camera is configured to shoot the sample image data during the test process; and the illuminating lamp is configured to provide an illuminating environment for the camera.

4. The wide-temperature-range uniaxial and biaxial compression test device in the high-pressure hydrogen environment according to claim 3, wherein an optical filter is arranged in front of a lens of the camera.

5. The wide-temperature-range uniaxial and biaxial compression test device in the high-pressure hydrogen environment according to claim 3, wherein: an observation window is formed on the test box, the observation window being encapsulated by explosion-proof glass; and the camera is configured to shoot the sample image data during the test process through the observation window.

6. The wide-temperature-range uniaxial and biaxial compression test device in the high-pressure hydrogen environment according to claim 1, wherein: the sample clamping mechanism comprises a first hydraulic telescopic rod, a second hydraulic telescopic rod, a third hydraulic rod, and a sample stage; the first hydraulic telescopic rod, the second hydraulic telescopic rod and the third hydraulic rod are electrically connected to the upper computer; each of the first hydraulic telescopic rod, the second hydraulic telescopic rod and the third hydraulic rod is provided with a corresponding one of the test pressure sensors and a corresponding one of the displacement sensors; an end of the first hydraulic telescopic rod is fixed to the test box, and a first pressure plate is arranged on another end of the first hydraulic telescopic rod; an end of the second hydraulic telescopic rod is fixed to the test box, and a second pressure plate is arranged on another end of the second hydraulic telescopic rod; an end of the third hydraulic telescopic rod is fixed to the test box, and a third pressure plate is arranged on another end of the third hydraulic telescopic rod; an end of the sample stage is fixed to the test box, and a sample placement end surface is formed on another end of the sample stage; the first pressure plate and the sample placement end surface are arranged oppositely; and the second pressure plate and the third pressure plate are arranged oppositely.

7. The wide-temperature-range uniaxial and biaxial compression test device in the high-pressure hydrogen environment according to claim 1, wherein the heating system comprises a plurality of heating tubes, the plurality of heating tubes are electrically connected to the upper computer, and the heating tubes are arranged on a box wall of the test box.

8. The wide-temperature-range uniaxial and biaxial compression test device in the high-pressure hydrogen environment according to claim 1, wherein the cooling system comprises a refrigerator, the refrigerator is electrically connected to the upper computer, and the refrigerator is arranged inside the test box.